Measuring reduction in stone tools: an ethnoarchaeological study of Gamo hidescrapers from Ethiopia Michael J. Shott a, * , Kathryn J. Weedman b,1 a Department of Classical Studies, Anthropology and Archaeology, University of Akron, Akron, OH 44325-1910, USA b Anthropology Program, University of South Florida, St. Petersburg, FL 33701, USA Received 8 May 2006; received in revised form 8 September 2006; accepted 11 September 2006 Abstract Stone tools were knapped, not built. This truism means that tools were reduced from larger pieces in the production process. But many tools were further reduced in use, to repair damage or as edges dulled. Reduction reduced size (trivially), but also changed the proportions among tools’ elements or dimensions. Such allometric variation (change in proportion as a function of change in size) is useful to estimate the degree of reduction that tools experienced. Reduction itself is a measure of curation, a theoretical concept of great interest in lithic studies and Paleo- lithic archaeology. To determine the reduction that archaeological tools experienced, we must compare their size and proportions at first use to the same properties at discard that we directly measure. By now many size estimates can be made from discarded tools. Some are experimentally tested but few are validated using direct ethnoarchaeological controls. We validate two allometric reduction measuresdratios of plan area to thickness and of an estimate of original to discarded volumedagainst direct measures of use and reduction in ethnographic Gamo hidescrapers from Ethiopia. Ó 2006 Elsevier Ltd. All rights reserved. Keywords: Reduction; Curation; Allometry; Hidescraper; Area:thickness 1. Introduction Their abundance makes stone tools one of archaeology’s most popular subjects. The range of lithic analysis befits such a common material, involving everything from source selection to use-wear to reveal the properties of ancient cultures and the details of ancient behavior. Perhaps the most common and one of the fundamental kinds of lithic analysis is simple typology, the act of assigning specimens to broad functional classes like ‘‘point’’ or ‘‘scraper’’ or to chronofunctional classes like ‘‘Kimberly point’’or ‘‘Mississippian hoe blade.’’ Of course typology is a legitimate goal of lithic analysis. In recent years, however, many archaeologists have assimilated the reduction thesis, the understanding that retouched tools vary progressively from first use to discard by decrease in size and change in form depending on extent and pattern of the resharpening that they experience. Not all tools are re- touched during use, so the reduction thesis is merely common, not universal. It is amply documented in many tool types from many times and places around the world (e.g., Andrefsky, 1997, 2006; Ballenger, 2001; Blades, 2003; Buchanan, 2006; Clarkson and Lamb, 2005; Dibble, 1995; Dibble, 1997; Flenniken and Wilke, 1989; Granger, 1978; Grimes and Grimes, 1985; Hiscock, 1996; Hiscock and Attenbrow, 2005; Hoffman, 1985; Jefferies, 1990; Kuhn, 1990; Lerner, 2004; Potts, 1991; Sahnouni et al., 1997; Shott, 1995, in press; Shott and Ballenger, in press; Shott and Sillitoe, 2004; Truncer, 1990; Weedman, 2002b). It also is documented in ethnographic sour- ces, mostly in unifaces for the simple reason that biface use is exceedingly rare in such accounts (e.g., Clark and Kurashina, 1981; Cooper, 1954; Gallagher, 1977; Haaland, 1987; Tindale, * Corresponding author. Tel.: þ1 330 972 6890; fax: þ1 330 972 2338. E-mail addresses: shott@uakron.edu (M.J. Shott), kjw@stpt.usf.edu (K.J. Weedman). 1 Tel.: þ1 727 553 4858. 0305-4403/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jas.2006.09.009 ARTICLE IN PRESS Please cite this article in press as: Michael J. Shott, Kathryn J. Weedman, Measuring reduction in stone tools: an ethnoarchaeological study of Gamo hidescrap- ers from Ethiopia, Journal of Archaeological Science (2006), doi:10.1016/j.jas.2006.09.009 Journal of Archaeological Science xx (2006) 1e20 http://www.elsevier.com/locate/jas + MODEL